Diaphragm pump



April 24, 1962 .1. E. PlccARDo 3,030,892

DIAPHRAGM PUMP Filed Feb. 25, 1960 United States Patent 3,030,892DIAPHRAGM PUMP Jaclr E. Piccardo, Gilliland, Calif., assigner to Dorr-Oliver Incorporated, Stamford, Conn.,v a corporation of Delaware FiledFeb. 23, 1960, Ser. No. 10,391 9 Claims. (Cl. 10S-44) This inventionrelates to improvements in pressure-fluid actuated diaphragm pumpswherein a diaphragm is actuated bythe pressure of a controlled fluidpressure medium admitted to one side of the diaphragm.

The invention provides a fluid actuated diaphragm pump particularlyadapted to handle coarse slurries or pulps, for example cement orconcrete which had presented problems because of the relatively largesolids and the resulting wear and tear on the parts and on the workingdiaphragm, and because of the possibility of overstretching of the pumpdiaphragm by the pressure of the operating fluid.

Diaphragm pumps employed for similar purposes suffer from a number ofdisadvantages, one of which is due to the fact that they are not readilycapable of passing coarse particles and may become jammed when largerpieces of material pass therethrough.

Furthermore, since it is preferable to operate such pumps with ratherhigh liuid operating pressures, such pressures may cause overstretchingor rupture of the working diaphragm, unless a backing surface isprovided dening the extreme outward position of the diaphragm. lf in theconventional pumps such a backing surface be presented by the associatedwall portion of the pump housing itself, solids are likely to gettrapped between the diaphragm and the wall as the slurry is beingdisplaced through the discharge outlet in this wall, leading to damageof the diaphragm. Also, under such conditions, the pressure of theactuating fluid may cause undesirable distension of an unsupportedportion of the diaphragm into the discharge opening, unless this isprevented by some perforated septum in the discharge opening. This mayalso be prevented by a perforated auxiliary backing wall across the pumphousing and spaced from the pump wall and from `the discharge opening.Yet, under slurry pumping conditions such as herein contemplated, anysuch perforated backing element is liable t plugging by the slurryparticles passing back and forth therethrough and thus offer undesirableflow resistance, also they are liable to excessive wear by the slurryparticles passing back and forth therethrough. Plugging occurs when theperforations are too small, but when the perforations are too large thedrawback is that the required amount of backing support is lost.

The present invention overcomes the aforementioned difficultiesencountered with diaphragm pumps now commonly in use for this purpose.This is achieved by a double diaphragm arrangement wherein the actuatingpressure from a fluid operating pressure medium such as water or airagainst an actuating diaphragm is transmitted to an associated workingdiaphragm through a pressure transfer liquid connedbetween the twodiaphragme. Each one of these diaphragms has a pre-formed dishedconfiguration which may assume bulging end conditions in oppositedirections at the respective ends of the stroke of the pump, yetautomatically so controlled thatvoverstretching of the working diaphragmis positively avoidable, irrespective of the amount of fluid operatingpressure applied to the working diaphragm.

According to the invention, this eiect is achieved by providing in thepump housing between the two diaphragme a foraminous backing platedish-shaped so as to conform to the predetermined pump stroke endposition of the operating diaphragm. r[he working diaphragm through3,039,892 Patented Apr. 24, 1962 ice the intervening confined body oftransmission uid attains a correspondingly shaped bulging configurationthat is without any stress on the diaphragm itself at the end of thepumping stroke. Thus the diaphragm is never overstressed since it neverengages a backing face or the like but is in free contact at all timeswith the slurry being pumped. To ensure this, the confined body oftransmission liquid must not exceed a predetermined maximum quantity.

According to a feature, the space between the diaphragm is incommunication with manually adjustable means for varying the amount ofiluid between the diaphragms.

Consequently, in the operation of the improved pump, regardless of theiiuid operating pressure (by either liquid or by air) applied to theactuating diaphragm, the pressure across the working diaphragm willalways equalize itself to the prevailing pumping head. ln this way, theworking diaphragm remains unrestrained and free-oating due to theequalized pressures on both sides thereof. Also, in case the suctionvalve should remain open on the pumping stroke while the outlet valve isnormal, then the pressure on the working diaphragm itself will be moreor less zero irrespective of what operating pressure is applied to theactuating diaphragm pressed against the foraminous backing plate.Furthermore, no plugging can occur in the foraminous backing plate sinceonly clear liquid and not slurry passes back and forth through theperforations.

According to another feature, the discharge end of the housing is soshaped that the working diaphragm in its retracted or innermost positionprovides with the housing an ample space or relatively large areathrough which may pass relatively large particles freely that are beingpumped through the apparatus. Also, in this way, the working diaphragmis always even in its outermost pumping strokeJ position, spaced fromthe adjacent walls of the housing, so that there is no possibility thatsolid material will be trapped between the working diaphragm and thehousing walls that would tend to cause abrasion and excessive Wear ofthe working diaphragm, and the two diaphragms themselves are maintainedin spaced relationship to each other due to the hydraulic pressuretransmitting liquid contained between them. The actuating diaphragm isoperated by suitable conventional iiuid pressure (water or air)operating mechanism, while the fluid disposed between the two diaphragmsalso serves as an effective means for conducting heat away from theworking diaphragm in case hot slurries are pumped so that the diaphragmwill not heat up excessively during operation.

An object of the present invention is the provision of a new and noveldouble diaphragm pump apparatus which is particularly adapted for use inpumping materials having relatively large objects therein such asconcrete and the like.

Another object of the invention is to provide a double diaphragm pumpapparatus wherein no special support means is required for the workingdiaphragm and which prevents excessive stretching of the workingdiaphragm.

A further object of the invention is the provision of a double diaphragmpump Iapparatus including means for l preventing excessive heating ofthe working diaphragm FIG. 1 illustrates a sectional view of anembodiment of the double diaphragm pump according to the presentinvention along with a diagrammatically illustrated operating mechanismfor the pump apparatus;

FIG. 2 illustrates a modified form of the invention incorporating adifferent type of working diaphragm.

Referring now to the drawings wherein like reference charactersdesignate corresponding parts throughout the views, there is shown inFIG. l a body means indicated generally by reference numeral andincluding three separate sections 11, 12 land 13 which are bolted to oneanother by nut and bolt assemblies 15. Section 11 of the body meansincludes an inlet portion 20 and an outlet portion 21. It should benoted that the outlet portion 21 is directed substantially horizontallywhile the inlet passage entering the pump from the inlet portion 20 isdirected downwardly at substantially ya 45 angle to the horizontal suchthat it may be said that the inlet and outlet portions have an angularrelationship to one another such that the inlet is directed at an angleof 45 to the outlet. This angular relationship is important incombination With the angular relationship of the longitudinal axis ofthe body means itself which is disposed at an angle of substantiallywith respect to the horizontal. This particular interrelationship asdescribed hereinafter cooperates to assist in passing large objectsthrough the pump.

Inlet portion is provided with suitable attaching flanges which arebolted to an attaching flange on a conduit 22. Conduit 22 is connectedwith a body portion of a check valve body indicated generally byreference numeral 23. A seat 24 is provided within the check valve body,and a ball 25 is adapted to rest upon seat 24 in sealing positiontherewith. Ball 25 is shown in sealing position in FIG. 1. An inletconduit 26 is connected to the lower portion of the check valve bodymeans, and the incoming slurry or pulp passes through inlet conduit 26in the direction of the arrow during operation.

During the suction of the pump, ball 25 is lifted into the dotted lineposition shown in FIG. l thereby providing a large passage Iarea forcoarse material through the check valve. It is evident that upon thepumping stroke of the pump, ball 25 will again be seated upon seat 24 ofthe valve to prevent reverse flow through the check valve. Outletportion 21 is also provided with attaching flanges which are secured tosuitable attaching flanges provided on a conduit 27. Conduit 27 is inturn connected with the lower portion of a second check valve body meansindicated generally by reference numeral 28 which is similar to thecheck valve body means 23 previously described. Disposed within thecheck valve body 28 is a valve seat 29 and a check ball 30 is adapted torest upon the valve seat in sealing relationship therewith.

'I'he outlet portion of valve body means 28 is connected with an outletconduit 31. It is evident that during the suction stroke of the pump,ball 38 will be urged into sealing engagement with seat 29 to close offthe connection of the pump with the outlet conduit. On the other hand,during the pumping stroke, ball 30 will be lifted off of the seat 29into the dotted line position to provide a relatively large passage areato permit the coarse materials to freely pass through the check valve.

Clamped between body sections 11 and 12 is a flexible deformable workingdiaphragm 40 formed of gum rubber or other suitable material and beingsealed with respect to the housing due to the clamping arrangement ofsections 11 and 12. An actuating diaphragm 41 of similar construction todiaphragm 40 is clamped between body sections 12 and 13 whereby theworking diaphragm and actuating diaphragm of the apparatus are normallydisposed in spaced relationship to one another.

A support member 42 is preferably formed integral with body section 12and comprises a rigid wall having la plurality of orifices 43 formedtherethrough. Wall 42 is provided with such a configuration that whenthe actuating diaphragm is in its normal fully extended pumping pumpingstroke position, it will conform to the configuration of supporting wall42 and be firmly supported thereby.

It will be noted that as seen in FIG. 1, a space 45 is defined betweenthe two diaphragms, or, stated another way, as seen in FIG. l, thisspace is defined between the working diaphragm and supporting wall 42.Disposed within this space is a suitable hydraulic fluid which isadapted to transmit movements of the actuating diaphragm 41 to theworking diaphragm 40. It is apparent that the orifices 43 in wall 42permit the hydraulic fluid in space 45 to pass freely through the wallportion whereby the working diaphragm will closely follow the movementsof the actuating diaphragm.

It is evident that the hydraulic fluid between the two diaphragms willprovide a good heat conductor such that heat Will be conducted away fromthe working diaphragm 40 and to further ensure that adequate cooling ofthe hydraulic fluid itself is obtained, a water cooling jacket space 46is provided by a wall portion 47 spaced from the outer wall of bodysection 12. Any suitable means may be provided for circulating coolingwater within the cooling jacket space.

A conduit 50 is disposed in communication with the space 45 between theactuating and working diaphragms, the opposite end of conduit 50 beingin communication with the interior of a hollow closed cylindricalhousing 51. A diaphragm 52 extends across` an intermediate portion ofthe housing 51, and hydraulic fluid is disposed within the space definedbetween flexible diaphragm 52 and the opposite end of the housing 51. Ascrew member 53 is threaded within the left end of the housing as seenin the drawing and is adapted to engage the flexible diaphragm 52. It isapparent that by adjusting the position of screw member 53, the positionof flexible diaphragm 52 may be varied to control the amount ofhydraulic fluid which is forced up into the space between the twodiaphragms. In this manner, the amount of fluid between the twodiaphragms may be altered to vary the stroke of the working diaphragmduring operation of the pump. For example, if the screw 53 were beingturned to move outwardly from the housing 51 thereby allowing foradditional storage space therein, there would result a shortening of theeffective pumping stroke of the working diaphragm 40 as indicated by thedot-and-dash end position D1 thereof, coordinated to the full line endposition D2 of the actuating diaphragm 41 which latter is supported bythe perforated wall 42. The correspondingly reduced effective volume ofconfined transmission uid is indicated by cross-hatching H1 in onedirection between diaphragm position D1 and D2. The respective oppositeend positions D3 and D4 respectively of the two diaphragms indicated indot-and-dash lines represent the condition at the end of the pumpsuction stroke. The confined transmission fluid is indicated by hatchedlines H2 in a different direction and the working diaphragm then inposition D3 resting against and backed up by the central portion of theperforated wall 42 preferably supplemented by an auxiliary marginal wall42 complementary to the central portion of wall 42 to constitutetherewith a dish-shaped backing surface which may be substantiallysymmetrical to the dish-shaped wall 42. Consequently, the hatched areasH, and H2 overlap in the peripheral annular space H3 between the backingwall 42 and the auxiliary backing wall 42a. When the full strokecapacity of the pump is to be used, the device 51, 52, 53 may bemanipulated so that overstressing of the working diaphragm at the end ofthe pumping stroke is partially avoided.

A clean-out openingis indicated at 55 in the side of the body means, andsuitable plugs are indicated at 56 and 57. It is apparent that variousdrain plugs and the like may be provided as desired within the bodymeans of the apparatus.

A threaded boss oil is formed in the central portion of body section 13and a nipple 61 is threaded therein and communicates with a cross pipefitting 62. A nipple 63 is threaded to one of the lateral sides ofiitting 62 and a nipple o4 is threaded to the opposite lateral side offitting 62. Nipples 63 and 64 are in turn in communication with solenoidoperated valves 65 and 66 respectively which in turn communicate withconduits 67 and 68 respectively which are connected to sources (notshown) of fluid under different pressures. For example, conduit 67 maycommunicate with a source of subatmospheric pressure while conduit 68may communicate with a source of atmospheric pressure or a source ofsubatmospheric pressure. Furthermore, gravity may be relied upon toeither charge or discharge the pump. If gravity is utilized to chargethe pump, then a positive pressure must be used to discharge the pump.If gravity is used to discharge the pump, then a subatmospheric pressuremust be used to charge the pump.

Solenoid valves 65 and 66 are operated through a conventional electriccircuit '70 from a timer or clock '71 of any suitable type. The fitting62 is also connected through a valve 74 to a pressure or vacuum gauge75. Clock mechanism 7l serves alternately to open and close solenoidvalves 65 and 66 and to cause the actuating diaphragm 4l to oscillatebetween its suction position wherein it is drawn up against body section13 to itsV pumping position shown in FIG. l wherein it is forced againstthe support wall.

It will be understood during operation that on the suction stroke ofactuating diaphragm 41, working diaphragm llt will be drawn into thedotted line position indicated at D3 in FIG. -1. As this suction strokeoccurs, the upper check valve will be open and the lower check valvewill be closed. lt is apparent that as the material enters the bodymeans, :it will be directed directly into the body means at an angle,and a relatively large area will be dened between the working diaphragmand portion 80 of body section 1l. This relatively large area is adaptedto easily accommodate any large particles of material which may be drawnin with the pumped uid. Such large particles will tend to settle to thebottom of the pump body means whereupon the inclination of the pump bodymeans itself with respect to the horizontal tends to move these largeparticles downwardly toward the outlet portion 2l of the pump.

Upon movement of the actuating diaphragm 41 in its pumping stroke,working diaphragm 4t) will be urged in a similar manner back toward thefull line position shown in FlG. l through the intermediary of thehydraulic fluid disposed between the two diaphragms, and the iluidwithin the pump will be urged outwardly through the outlet portion 21and the outlet conduit 3l. During this pumping stroke, the upper checkvalve will be closed and the lower check valve will be open. lf it isdesired to vary the pump output as by shortening the stroke of theworking diaphragm, the amount of liquid between the two diaphragms maybealtered by actuating screw member 53.

Referring now to FIG. 2 of the drawing, a modification is illustratedwherein the body means is indicated generally by reference numeral 8l,the body means including an inlet portion and an outlet portion, alongwith associated check valve mechanisms (not shown) in a manner similarto that described in connection with FIG. l.

An actuating diaphragm 86 is provided similar to diaphragm 4l of thedevice shown in FIG. 1 which is in communication with a similaroperating mechanism through a threaded boss 87. The actuating diaphragm86 coopcrates with a supporting wall portion 83 similar to wall portion42 and being provided with a plurality of orilices S9. The primarydistinction of the apparatus shown in FiG. 2 over that shown in FIG. lis the mode of construction of the working diaphragm 90. In themodification shown in FIG. 2, this working diaphragm is in the form of abellows and includes a corrugatedside wall portion 91, this corrugatedportion being preferably reinforced by a plurality of wires 92. Withthis type of construction, the diaphragm may be formed of Teon which isa very desirable material to employ in chemical pumping operations. Teoncan not normally stand the exing encountered if it is fabricated as adiaphragm shown in FIG. l, but it is adapted to be formed as a bellowswhich is compressed by the actuating diaphragm during operation. It willbe understood that the operation of the apparatus shown in FIG. 2 issubstantially the same as that shown in FlG. l.

In order to provide an additional safety feature, a photoelectric cell(not shown) may be mounted in the body section -12 between the twodiaphragms in Such a position that it is in communication with the spacedened between the diaphragms and is adapted to sense changes in thefluid in such space. The photoelectric cell can be connected wtih asuitable alarm bell or the like such that if the working diaphragmshould fail, the mixing of the pumped iluid with the hydraulic fluidwould be sensed by the photoelectric cell thereby sounding the alarmbell. This safety feature may be important when hazardous liquids andslurries are being pumped and an immediate indication would be providedwhen replacement of theA working diaphragm is required.

It is apparent from the foregoing that there is provided a new and noveldouble diaphragm pump apparatus which is particularly adapted to pumpmaterials having relatively large objects therein and which is adaptedto operate under high pressures without damages to the diaphragmsthereof. No special support is required for the working diaphragm in theapparatus, and in addition, the working diaphragm can not be excessivelystretched during operation. This is insured by ythe provision of thesupport wall between the two diaphragms which positively limits pumpingmovement of the actuating diaphragm and accordingly thereby also limitsthe pumping movement of the working diaphragm. The hydraulic fluid alsoserves as an etlcient means for conducting heat away from the workingdiaphragm. The overall structural arrangement is such that the solidmaterials can not be trapped between the working diaphragm and the bodymeans thereby reducing abrasion and wear of the working diaphragm to aminimum. In addition, pressures on opposite sides of the workingdiaphragm are equalized regardless of the discharge head conditions. Theapparatus is also quite simple and inexpensive in construction and yetis sturdy and reliable in operation.

As this invention may be embodied in several forms Without departingfrom the spirit or essential characteristics thereof, the presentembodiment is therefore illusltrative and not restrictive, and sincelthe scope of the invention is dened by the appended claims, all changesthat fall within the metes and bounds of the claims or that form theirfunctional as Well as conjointly cooperative equivalents are thereforeintended to be embraced by those claims.

I claim:

1. In a Huid-actuated double diaphragm pump wherein the pump housing is`divided by the diaphragms into an actuating chamber for the actuatingiiuid, a pumping chamber, and an intermediate fluid pressuretransmission chamber between said actuating chamber and said pumpingchamber, the arrangement which comprises an intermediate substantiallycylindrical housing section formed with a flange at each end and havingtransverse extending foraminous partition means integral and mergingwith one flanged end thereof, and shaped to conform to4 and said closuremeans and adapted to conformingly engage said foraminous partitionmeans; a housing end section for closing the other end of saidintermediate housing section and having intake means and dischargemeans, to constitute the pumping chamber; and working diaphragm meansheld between said intermediate housing section and said housing endsection, and defining with said other diaphragm and with saidintermediate housing section the intermediate fluid transmissionchamber.

2. The arrangement according to claim l with the addition of a heatexchange jacket surrounding said intermediate housing section unitarytherewith.

3. In a fluid-actuated double diaphragm pump wherein the pump housing isdivided by the diaphragms into an actuating chamber for the operatingfluid, a pumping chamber, and an intermediate fluid pressuretransmission chamber between said actuating chamber and said pumpingchamber, the arrangement which comprises an intermediate substantiallycylindrical housing section formed with a flange at each end; atransverse extending foraminous partition means associated with oneflanged end of said housing section, and shaped to conform to theactuating diaphragm means defined below, a flanged cover means forclosing the one flanged end of said intermediate housing section; adished actuating diaphragm means held between the associated flanges ofsaid intermediate housing section and said cover means and adapted toconformingly engage said foraminous partition means; a

flanged housing end section for closing the other flanged end of saidintermediate housing section and having in take means and dischargemeans for pumping, a working diaphragm means held between the associatedflanges of said intermediate housing section and said housing endsection, and defining with said other diaphragm and with saidintermediate housing section the intermediate fluid transmissionchamber; and a heat exchange chamber surrounding said intermediatehousing section and defined by the cylindrical wall of said housingsection, furthermore by the flanges thereof, and also by an outer Wallsurrounding said cylindrical wall and having its ends connected torespective flanges of said housing section.

4. In a fluid-actuated double diaphragm pump for pumping slurry or thelike, wherein the pump housing is divided by the diaphragms into anactuating chamber for the actuating fluid, a pumping chamber, and afluid pressure transmission chamber intermediate said actuating chamberand said pumping chamber, the arrangement which comprises anintermediate substantially cylindrical housing section formed with aflange at each end, transverse foraminous partition means integral withsaid cylindrical housing section, comprising a pair of marginal annularportions each extending inwardly from a respective flanged end portionof said housing section integral therewith and merging with each otherin a common central portion, said partition means presenting each inrespective outward axial direction a surface contour substantiallyshaped to conform to the shape of respective diaphragm means definedbelow; a flanged closure means for the one flanged end of saidintermediate housing section and with said foraminous partition meansconstituting said actuating chamber; a dished actuating diaphragm meansheld between the associated flanges of said intermediate housing sectionand `said closure means and adapted to conformingly engage saidforaminous partition means; a flanged housing end section for closingthe other flanged end of said intermediate housing section and havingintake means and discharge means, to constitute the pumping chamber; andworking diaphragm means held between the associated flanges of saidintermediate housing section and said housing end section, and definingwith said other diaphragm and with said intermediate housing section theintermediate fluid transmission chamber.

5. The arrangement according to claim 4, with the addition of a heatexchange chamber surrounding said intermediate housing section anddefined by the cylindrical wall of said housing section, and by theflanges thereof,

as Well as by the outer wall surrounding said cylindrical wall andhaving its ends connected to respective flanges of said intermediatehousing sections.

6. The arrangement according to claim 4, wherein the longitudinal axisof said intermediate housing section constitutes an acute angle with thehorizontal, and wherein said intake means comprise an upwardly inclinedintake neck portion, and said discharge means comprise a discharge neckportion located below said intake neck portion and directed at an anglewith respect thereto, constituting a pump chamber shaped like a Y lyingon its side adapted to facilitate gravitational passage of the slurrythrough said chamber.

7. In a fluid actuated double diaphragm pump for pumping slurry or thelike, wherein the pump housing is divided by the diaphragms into anactuating chamber for the operating fluid, a pumping chamber, and afluid pressure transmission chamber intermediate said actuating chamberand said pumping chamber, the arrangement which comprises anintermediate substantially cylindrical housing section formed with aflange at each end with the longitudinal axis thereof extending at anacute angle to the horizontal declining towards the pumping chamber; atransverse foraminous partition means provided in said housing section,shaped to conform to the actuating diaphragm means defined below; aflanged closure means for the one end of the intermediate housingsection and with said foraminous partition means constituting saidactuating chamber; a dished actuating diaphragm means held between theassociated flanges of said intermediate housing section and said covermeans and adapted to conformingly engage said foraminous partitionmeans; a flanged housing end section for closing the other flanged endof said intermediate housing section, said section having an upwardlydirected intake neck portion, and a discharge neck portion located belowsaid intake neck portion and directed at an angle with respect thereto,constituting a pump chamber shaped like a Y lying on its side adapted tofacilitate gravitational passage of the slurry through said chamber; andworking diaphragm means held between the associated flanges of saidintermediate housing section and said housing end section.

8. In a fluid-actuated double diaphragm pump, wherein the pump housingis divided by the diaphragms into an actuating chamber for the operatingfluid, a pumping chamber, and a fluid pressure transmission chamberintermediate said actuating chamber and said pumping chamber, thearrangement which comprises an intermediate substantially cylindricalhousing section formed with a flange at each end; a transverseforaminous partition means at one end of said housing section, shaped toconform to the actuating diaphragm means defined below; a flangedclosure means for said one end of the intermediate housing section andwith said foraminous partition means constituting -said actuatingchamber; a dished actuating diaphragm means held between the associatedflanges of said intermediate housing section and said closure means andadapted to conformingly engage said foraminous partition means; aflanged housing end section for closing the other end of saidintermediate housing section and having intake means add dischargemeans, constituting a working diaphragm means held between theassociated flanges of said intermediate housing section and said housingend section, and comprising an accordion-shaped body portion extendingfrom said flanges towards said foraminous partition; and a heatexchanger chamber surrounding said intermediate housing portion anddefined by the cylindrical wall of said housing portion, furthermore bythe flanges thereof, as well as by an outer wall surrounding saidcylindrical wall and having its ends connected to respective flanges ofsaid housing portion.

9. In a fluid-actuated double diaphragm pump for pumping slurry or thelike, wherein the pump housing is divided by the diaphragms into anactuating chamber for the operating uid, a pumping chamber, and a uidpressure transmission chamber intermediate said actuating chamber andsaid pumping chamber; the arrangement which comprises an intermediatesubstantially cylindrical housing section formed with a ange at eachend, with the longitudinal axis thereof extending at an acute angle tothe horizontal declining towards the pumping chamber; a transverseforaminous partition means at one end of said housing section, shaped toconform tothe actuating diaphragm means defined below; a anged closuremeans for closing said one end of the intermediate housing section andwith said foraminous partition means constituting said actuatingchamber; a dished actuating diaphragm means held between the associatedange of said cover means and adapted -to conformingly engage saidIforaminous partition means; a flanged housing end section for closingthe other anged end of said intermediate housing section, said sectionhaving an upwardly directed intake neck portion and a discharge neckportion `located below said intake neck portion and directed at an anglewith respect thereto, constituting a pump chamber shaped like a Y lyingon its side adapted to facilitate gravitational passage of the slurrythrough said chamber; and a working diaphragm means held between theassociated flanges of said intermediate housing section and said endhousing section, and comprising an accordion-shaped body portionextending from said anges Itoward said foraminous partition.

References Cited in the tile of this patent UNITED STATES PATENTS1,650,377 Nixon Nov. 22, 1927 2,311,229 Herbert Feb. 16, 1943 2,827,853Bradley Mar. 25, 1958 2,950,396 Schneider Ang. 23, 1960 FOREIGN PATENTS147,826 Sweden Nov. 23, 1954 376,842 Great Britain Apr. 14, 1932 673,850France Oct. 14, 1929

